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Inches to Millimeters

Convert in to mm instantly using a precise conversion factor.

inmm
in
=
mm
✓ Instant calculation✓ Accurate factor✓ No signup

How to convert in to mm

Multiply inches by 25.4. The calculator applies this relationship immediately and supports positive, negative, and decimal values where appropriate.

This conversion is commonly useful for fasteners, manufacturing, woodworking, and technical drawings.

Inches to Millimeters reference table

inmm
1 in25.4 mm
5 in127 mm
10 in254 mm
25 in635 mm
100 in2540 mm

Worked example

For 10 in, multiply 10 by 25.4. The result is 254 mm.

How do you convert in to mm?

Multiply inches by 25.4.

Can I use decimal values?

Yes. Enter any decimal value and the result updates automatically.

More length conversions

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